Dijkstra

n,s,f = map(int, input().split())
s-=1
f-=1

INF = 1000000000

Dist = [ 0 ] *n
for i in range(n):
    Dist[i] = list ( map( int, input().split() ) )

d = [ INF ] * n
u = [ False ] *n
d[s] = 0

for i in range(n):
    minv = -1
    for j in range(n):
        if not u[j] and (minv == -1 or d[minv] > d[j] ):
            minv = j

    if d[minv] == INF:
        break

    u[minv] = True
    for j in range(n):
        if Dist[minv][j] != -1:
            d[j] = min ( d[j], d[minv] + Dist[minv][j] )

if d[f] == INF:
    print(-1)
else:
    print(d[f])